Definition
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Edgar Bailey
Unknown
Etymology
From French schiste, Greek skhistos i.e. split
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Blue, Bluish - Grey, Purple, Shades of Blue
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Dull and Banded
Dull and Soft
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
-
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Creating Artwork, Gemstone
Types
Metamorphic rock
Cataclastic rock
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Formation
Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
-
Grain Size
Fine to Medium Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White to Grey
Light to dark brown
Porosity
Highly Porous
Less Porous
Specific Gravity
3-3.2
2.46-2.86
Transparency
Opaque
Transparent to Translucent
Density
2.8-2.9 g/cm3
2.7-2.9 g/cm3
Resistance
Impact Resistant, Pressure Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Japan, Turkey
South Korea
Africa
Egypt, Ethiopia, South Africa
Western Africa
Europe
France, Greece, Iceland
Great Britain, Switzerland
Deposits in Western Continents
Deposits in Oceania Continent
Australia
New Zealand
Central Australia, Western Australia
All about Blueschist and Pseudotachylite Properties
Know all about Blueschist and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Blueschist and Pseudotachylite belong to Metamorphic Rocks.Texture of Blueschist is Foliated whereas that of Pseudotachylite is Quench. Blueschist appears Dull and Banded and Pseudotachylite appears Dull and Soft. The luster of Blueschist is dull while that of Pseudotachylite is vitreous. Blueschist is available in blue, bluish - grey, purple, shades of blue colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Blueschist are cemetery markers, commemorative tablets, creating artwork, curling, tombstones and that of Pseudotachylite are creating artwork, gemstone.